Nickel Nanoparticles Decorating Graphite Flake Surface Using Planetary Ball Milling: Physical Characterization and Methanol Electrooxidation Investigation

Abstract

In recent years, several researches have been conducted in order to investigate the physical and chemical method for obtain the metallic nanoparticles, such as co-precipitation, hydrothermal, thermal decomposition of organometallic compounds, electrochemical, and ball milling method [1-4]. The particle size, shape and crystallinity depend on the selected synthesis method. In this sense the ball milling technique is one of the widely used to produce metallic nanoparticles, being the method feasible for large production [4]. A simple approach was proposed to obtain graphite surface decorated with nickel nanoparticles (Ni NPs) from dry ball milling process. Ni NPs were obtained after 40 h of high energy milling and 100, 200, 300 and 400 rpm ball rotation speeds. Both Ni NPs and graphite decorated samples were characterized by Scanning Transmission (STEM), Raman Spectroscopy, Scanning Electron Microscopy, X-ray diffraction pattern (XRD). The electrocatalytic activity of Ni/Graphite samples were evaluated from methanol oxidation in alkaline medium using electrochemical techniques. Good agreement between STEM and XRD results can be found, reporting average diameter size of 4.9 nm and average crystallite size of 5.50 nm for Ni NPs. The methanol electrooxidation electrocatalytic activity was more efficient for Ni/Graphite with 100 rpm compared to Ni/Graphite others. REFERENCES M. Freire, T.S. Ribeiro, I.F. Vasconcelos, J.C. Denardin, E.B. Barros, M. Giuseppe, L. Carbone, S.E. Mazzetto, P.B.A. Fechine, MZnFe2O4 (M = Ni, Mn) cubic superparamagnetic nanoparticles obtained by hydrothermal synthesis, J. Nanopart. Res. 15 (2013) 1-12.Alonso, P. Riente, J.A. Sirvent, M. Yus, Nickel nanoparticles in hydrogen-transfer reductions: Characterisation and nature of the catalyst, Appl. Catal. A 378 (2010) 42–51.Aghazadeh, A.N. Golikand, M. Ghaemi, Synthesis, characterization, and electrochemical properties of ultrafine b-Ni(OH)2 nanoparticles, Int. J. Hydrogen Energy 36 (2011) 8674-8679.F. de Carvalho, S.N. de Medeiros, M.A. Morales, A.L. Dantas, A.S. Carriço, Synthesis of magnetite nanoparticles by high energy ball milling Appl. Surf. Sci. 275 (2013) 84-87.